Royal
Tern Sterna
maxima

At a glance

Largest
breeding tern in the region Uncommon
breeding species in West Indies Wintering,
and first-second year birds from North American nesting colonies common
throughout region Colonial,
lay single egg

Index

Identification

One
of two large
white terns in our area. Larger Caspian Tern occurs only as a migrant
and winter resident in region. Royal Tern is 46-53 cm (18-21 inches)
total length. White with long, uniform orange bill. Has less black in
underwing than Caspian Tern. Royal more likely to be seen far at sea;
less likely to be seen inland. Breeding
adults have black caps, immatures and non-breeding adults have band of
dark plumage extending from eyes over the backs of their heads.

Adults

Can
live to ages
of 27-28 years, perhaps longer. Most begin breeding at 5-6 years.
Breeding adults have shaggy black cap. Pale grey dorsal surface,
underparts white. White, deeply forked tail. Non-breeding individuals
have only black streak through eye and across nape. Tail not forked and
grey. Legs black in adults.

Juveniles

Remain
on wintering ground for at least first two winters. Legs light orange
to yellow. Partial black cap.

Alternative Names

Systematics

One
of a number
of species of crested terns that collectively have
cosmopolitan
distribution. Two subspecies: only one in the Americas is the nominate.
The other subspecies is smaller, and breeds along the west central
coast of Africa.

Likely locations

Coastal
areas
throughout region, as breeding species primarily in Bahamas and US
Virgin Islands. Typically feeds inshore but can forge far at sea.

Distribution

Sterna m. maxima
primarily a temperate breeder, but also nests in Central America and
West Indies Region. Breeds in coastal areas Virginia south to
Texas, eastern Mexico, northern South America and disjunct populations
from southeastern Brazil to Argentina. In Pacific: western North
America
from southern California through Gulf of California. In western North
Atlantic winters from Carolinas south through Guff of Mexico, Caribbean
and Atlantic coast of South America.

Biology

At
sea

This
species,
like most of the other white terns most commonly feeds inshore.
Primarily diurnal but some nocturnal feeding. Off North Carolina they
regularly fly 35 miles or more out to sea to hunt and then return to
barrier islands to feed their chicks, so perhaps this occurs in other
areas as well. In Gulf Stream feeds along oceanic fronts and over
feeding schools of coastal and pelagic fishes. Often seen at sea
perched on drifting boards and logs. Most references, however, consider
this to be an inshore and coastal species. Feed primarily by plunge
diving from heights of 5-10 meters. Feed on relatively large fish. Also
eat shrimp and squid.

At
the nest

Ground
nesting
colonial species, nest is a simple depression. Nesting in open sandy
areas often with Sandwich Terns. Breeding activity and colony formation
begins in April. Normally only one egg. Color and pattern highly
variable as used by parents to recognize their own egg. Ground color
varies from whitish to dark brown and heavily spotted usually at broad
end. Incubation period 30-31 days. Leave nest in first week and form
crèches. Young fledge in 28-35 days but young continue to be feed by
parents, following them to wintering grounds. Parent young association
continues until March.

Current Population

West
Indies (WIBSA data)

Sites

Low
Estimate

High
Estimate

Bahamas

14

247

317

Turks
and Caicos

4

320

335

Cuba

13

33

111

Jamaica

2

11

11

Dominican
Republic

1

10

20

Puerto
Rico

3

12

21

US
Virgin Islands

7

47

195

Anguilla

3

155

155

St.
Maarten

1

47

47

St.
Barts

1

30

50

Montserrat

2

2

20

Martinique

1

0

10

Grenada

2

2

20

Tobago

2

1

20

Venezuela

11

43

165

Bonaire

1

85

85

Aruba

1

1

2

French
Guyana

1

100

100

Total

70

1146

1684

Areas
outside West Indies

Breeding
Pairs

Source

Central
Atlantic States

4734

Buckley
and
Buckley 1984

SE
United States

62532

Clapp
and Buckley 1984

Islands
off Yucatan

1000

Howell
and Webb 1995

Total
for Western North Atlantic

70000
(50000-75000)

Kushlan
et al. 2002

Gulf
of California

8000-10000

Everett
and Anderson 1991

South
Atlantic

Size
unknown

Recent
Discovery

Conservation Status

Not a
species of
conservation concern, but rare in West Indies region. Known to be
extirpated from several cays in US Virgin Islands.

Compiled
by: Dave Lee and Will Mackin

West
Indian Breeding Seabird Atlas by Will
Mackin and David Lee is licensed
under a Creative
Commons Attribution-Noncommercial-No Derivative Works 3.0 United States
License. Based on
work at www.wicbirds.net.
Permissions beyond the scope of this license may be available at www.wicbirds.net.